Study of the nerve endings and mechanoreceptors of the medial meniscotibial ligament of the knee: A structural and distribution analysis.

BACKGROUND: The aim of the present study is to describe the morphology and distribution of the nerve endings of the meniscotibial ligament (MTL) of the knee, in order to understand the interaction between the proprioceptive system and knee mechanics. METHODS: Twenty medial MTLs were obtained from deceased organ donors. The ligaments were measured, weighed and cut. Sections (10 mm) were prepared on hematoxylin and eosin-stained slides for analysis of tissue integrity, and 50 mm sections were submitted to immunofluorescence with the protein gene product (PGP) 9.5 as primary antibody and Alexa Fluor 488 as secondary antibody, followed by microscopic analysis. RESULTS: The medial MTL was identified in 100% of the dissections, with average length, width, thickness and weight of 7.07 ± 1.34 mm, 32.25 ± 3.09 mm, 3.53 ± 0.27 mm and 0.67 ± 0.13 g, respectively. The hematoxylin and eosin-stained histological sections exhibited typical ligament structure, with dense well-organized collagen fibers and vascular tissue. All the specimens analyzed contained type I (Ruffini) mechanoreceptors and free (type IV) nerve endings, varying from parallel to intertwined fibers. Nerve endings not classified with different irregular shapes were also found. Most type I mechanoreceptors were found close to the MTL insertions on the tibial plateau, while the free nerve endings were found adjacent to the capsule. CONCLUSION: The medial MTL showed a peripheral nerve structure, primarily type I and IV mechanoreceptors. These findings suggest that the medial MTL is important for proprioception and medial knee stabilization.

Fracture of the Humeral Shaft Associated to Elbow Dislocation and Fracture of the Distal-third of the Forearm: Case Report.

Humeral shaft fractures combined with elbow dislocation and fracture of the distal third of the bones of the forearm are uncommon. No description of this simultaneous association has been found in the same patient. Some studies report the association of these two lesions; however, no reports on the three ipsilateral lesions have been found at the PubMed, Lilacs and Bireme databases. The present report describes a case that occurred in a 13-year-old boy who suffered a fall from a height of approximately three meters and was admitted to a trauma hospital. Radiographs showed an ipsilateral humeral shaft fracture combined with elbow dislocation and a fracture of the distal-third of the bones of the forearm. Under general anesthesia, the injuries were readily reduced by closed manipulation, obtaining a satisfactory reduction of the injuries. Following this, an antebrachiopalmar splint and a commercial Velpeau shoulder immobilizer for the treatment of the humerus diaphyseal fracture were used. After 1 week, the patient presented non-alignment of the diaphyseal fracture of the humerus and was submitted to surgical treatment with flexible retrograde intramedullary nailing, antebrachiopalmar cast, and a commercial Velpeau shoulder immobilizer.